[PATCH v2 2/3] clk: add Dove PLL divider support for GPU, VMeta and AXI clocks

Russell King
2015-12-06T23:28:32Z

Add support for the Dove PLL dividers, which are used to generate the
clocks for the AXI bus, as well as the GPU and VMeta peripherals.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
drivers/clk/mvebu/Makefile | 2 +-
drivers/clk/mvebu/dove-divider.c | 262 +++++++++++++++++++++++++++++++++++++++
drivers/clk/mvebu/dove.c | 6 +
3 files changed, 269 insertions(+), 1 deletion(-)
create mode 100644 drivers/clk/mvebu/dove-divider.c

diff --git a/drivers/clk/mvebu/Makefile b/drivers/clk/mvebu/Makefile
index 645ac7ea3565..8866115486f7 100644
--- a/drivers/clk/mvebu/Makefile
+++ b/drivers/clk/mvebu/Makefile
@@ -7,6 +7,6 @@ obj-$(CONFIG_ARMADA_375_CLK) += armada-375.o
obj-$(CONFIG_ARMADA_38X_CLK) += armada-38x.o
obj-$(CONFIG_ARMADA_39X_CLK) += armada-39x.o
obj-$(CONFIG_ARMADA_XP_CLK) += armada-xp.o
-obj-$(CONFIG_DOVE_CLK) += dove.o
+obj-$(CONFIG_DOVE_CLK) += dove.o dove-divider.o
obj-$(CONFIG_KIRKWOOD_CLK) += kirkwood.o
obj-$(CONFIG_ORION_CLK) += orion.o
diff --git a/drivers/clk/mvebu/dove-divider.c b/drivers/clk/mvebu/dove-divider.c
new file mode 100644
index 000000000000..d5c5bfa35a5a
--- /dev/null
+++ b/drivers/clk/mvebu/dove-divider.c
@@ -0,0 +1,262 @@
+/*
+ * Marvell Dove PMU Core PLL divider driver
+ *
+ * Cleaned up by substantially rewriting, and converted to DT by
+ * Russell King. Origin is not known.
+ */
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#include "dove-divider.h"
+
+struct dove_clk {
+ const char *name;
+ struct clk_hw hw;
+ void __iomem *base;
+ spinlock_t *lock;
+ u8 div_bit_start;
+ u8 div_bit_end;
+ u8 div_bit_load;
+ u8 div_bit_size;
+ u32 *divider_table;
+};
+
+enum {
+ DIV_CTRL0 = 0,
+ DIV_CTRL1 = 4,
+ DIV_CTRL1_N_RESET_MASK = BIT(10),
+};
+
+#define to_dove_clk(hw) container_of(hw, struct dove_clk, hw)
+
+static void dove_load_divider(void __iomem *base, u32 val, u32 mask, u32 load)
+{
+ u32 v;
+
+ v = readl_relaxed(base + DIV_CTRL1) | DIV_CTRL1_N_RESET_MASK;
+ writel_relaxed(v, base + DIV_CTRL1);
+
+ v = (readl_relaxed(base + DIV_CTRL0) & ~(mask | load)) | val;
+ writel_relaxed(v, base + DIV_CTRL0);
+ writel_relaxed(v | load, base + DIV_CTRL0);
+ ndelay(250);
+ writel_relaxed(v, base + DIV_CTRL0);
+}
+
+static unsigned int dove_get_divider(struct dove_clk *dc)
+{
+ unsigned int divider;
+ u32 val;
+
+ val = readl_relaxed(dc->base + DIV_CTRL0);
+ val >>= dc->div_bit_start;
+
+ divider = val & ~(~0 << dc->div_bit_size);
+
+ if (dc->divider_table)
+ divider = dc->divider_table[divider];
+
+ return divider;
+}
+
+static int dove_calc_divider(const struct dove_clk *dc, unsigned long rate,
+ unsigned long parent_rate, bool set)
+{
+ unsigned int divider, max;
+
+ divider = DIV_ROUND_CLOSEST(parent_rate, rate);
+
+ if (dc->divider_table) {
+ unsigned int i;
+
+ for (i = 0; dc->divider_table[i]; i++)
+ if (divider == dc->divider_table[i]) {
+ divider = i;
+ break;
+ }
+
+ if (!dc->divider_table[i])
+ return -EINVAL;
+ } else {
+ max = 1 << dc->div_bit_size;
+
+ if (set && (divider == 0 || divider >= max))
+ return -EINVAL;
+ if (divider >= max)
+ divider = max - 1;
+ else if (divider == 0)
+ divider = 1;
+ }
+
+ return divider;
+}
+
+static unsigned long dove_recalc_rate(struct clk_hw *hw, unsigned long parent)
+{
+ struct dove_clk *dc = to_dove_clk(hw);
+ unsigned int divider = dove_get_divider(dc);
+ unsigned long rate = DIV_ROUND_CLOSEST(parent, divider);
+
+ pr_debug("%s(): %s divider=%u parent=%lu rate=%lu\n",
+ __func__, dc->name, divider, parent, rate);
+
+ return rate;
+}
+
+static long dove_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent)
+{
+ struct dove_clk *dc = to_dove_clk(hw);
+ unsigned long parent_rate = *parent;
+ int divider;
+
+ divider = dove_calc_divider(dc, rate, parent_rate, false);
+ if (divider < 0)
+ return divider;
+
+ rate = DIV_ROUND_CLOSEST(parent_rate, divider);
+
+ pr_debug("%s(): %s divider=%u parent=%lu rate=%lu\n",
+ __func__, dc->name, divider, parent_rate, rate);
+
+ return rate;
+}
+
+static int dove_set_clock(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct dove_clk *dc = to_dove_clk(hw);
+ u32 mask, load, div;
+ int divider;
+
+ divider = dove_calc_divider(dc, rate, parent_rate, true);
+ if (divider < 0)
+ return divider;
+
+ pr_debug("%s(): %s divider=%u parent=%lu rate=%lu\n",
+ __func__, dc->name, divider, parent_rate, rate);
+
+ div = (u32)divider << dc->div_bit_start;
+ mask = ~(~0 << dc->div_bit_size) << dc->div_bit_start;
+ load = BIT(dc->div_bit_load);
+
+ spin_lock(dc->lock);
+ dove_load_divider(dc->base, div, mask, load);
+ spin_unlock(dc->lock);
+
+ return 0;
+}
+
+static const struct clk_ops dove_divider_ops = {
+ .set_rate = dove_set_clock,
+ .round_rate = dove_round_rate,
+ .recalc_rate = dove_recalc_rate,
+};
+
+static struct clk *clk_register_dove_divider(struct device *dev,
+ struct dove_clk *dc, const char **parent_names, size_t num_parents,
+ void __iomem *base)
+{
+ char name[32];
+ struct clk_init_data init = {
+ .name = name,
+ .ops = &dove_divider_ops,
+ .parent_names = parent_names,
+ .num_parents = num_parents,
+ };
+
+ strlcpy(name, dc->name, sizeof(name));
+
+ dc->hw.init = &init;
+ dc->base = base;
+ dc->div_bit_size = dc->div_bit_end - dc->div_bit_start + 1;
+
+ return clk_register(dev, &dc->hw);
+}
+
+static DEFINE_SPINLOCK(dove_divider_lock);
+
+static u32 axi_divider[] = {-1, 2, 1, 3, 4, 6, 5, 7, 8, 10, 9, 0};
+
+static struct dove_clk dove_hw_clocks[4] = {
+ {
+ .name = "axi",
+ .lock = &dove_divider_lock,
+ .div_bit_start = 1,
+ .div_bit_end = 6,
+ .div_bit_load = 7,
+ .divider_table = axi_divider,
+ }, {
+ .name = "gpu",
+ .lock = &dove_divider_lock,
+ .div_bit_start = 8,
+ .div_bit_end = 13,
+ .div_bit_load = 14,
+ }, {
+ .name = "vmeta",
+ .lock = &dove_divider_lock,
+ .div_bit_start = 15,
+ .div_bit_end = 20,
+ .div_bit_load = 21,
+ }, {
+ .name = "lcd",
+ .lock = &dove_divider_lock,
+ .div_bit_start = 22,
+ .div_bit_end = 27,
+ .div_bit_load = 28,
+ },
+};
+
+static const char *core_pll[] = {
+ "core-pll",
+};
+
+static int dove_divider_init(struct device *dev, void __iomem *base,
+ struct clk **clks)
+{
+ struct clk *clk;
+ int i;
+
+ /*
+ * Create the core PLL clock. We treat this as a fixed rate
+ * clock as we don't know any better, and documentation is sparse.
+ */
+ clk = clk_register_fixed_rate(dev, core_pll[0], NULL, CLK_IS_ROOT,
+ 2000000000UL);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ for (i = 0; i < ARRAY_SIZE(dove_hw_clocks); i++)
+ clks[i] = clk_register_dove_divider(dev, &dove_hw_clocks[i],
+ core_pll,
+ ARRAY_SIZE(core_pll), base);
+
+ return 0;
+}
+
+static struct clk *dove_divider_clocks[4];
+
+static struct clk_onecell_data dove_divider_data = {
+ .clks = dove_divider_clocks,
+ .clk_num = ARRAY_SIZE(dove_divider_clocks),
+};
+
+void __init dove_divider_clk_init(struct device_node *np)
+{
+ void *base;
+
+ base = of_iomap(np, 0);
+ if (WARN_ON(!base))
+ return;
+
+ if (WARN_ON(dove_divider_init(NULL, base, dove_divider_clocks))) {
+ iounmap(base);
+ return;
+ }
+
+ of_clk_add_provider(np, of_clk_src_onecell_get, &dove_divider_data);
+}
diff --git a/drivers/clk/mvebu/dove.c b/drivers/clk/mvebu/dove.c
index b8c2424ac926..59fad9546c84 100644
--- a/drivers/clk/mvebu/dove.c
+++ b/drivers/clk/mvebu/dove.c
@@ -17,6 +17,7 @@
#include <linux/io.h>
#include <linux/of.h>
#include "common.h"
+#include "dove-divider.h"

/*
* Core Clocks
@@ -184,9 +185,14 @@ static void __init dove_clk_init(struct device_node *np)
{
struct device_node *cgnp =
of_find_compatible_node(NULL, NULL, "marvell,dove-gating-clock");
+ struct device_node *ddnp =
+ of_find_compatible_node(NULL, NULL, "marvell,dove-divider-clock");

mvebu_coreclk_setup(np, &dove_coreclks);

+ if (ddnp)
+ dove_divider_clk_init(ddnp);
+
if (cgnp)
mvebu_clk_gating_setup(cgnp, dove_gating_desc);
}
--
2.1.0